1. Field of Invention
The disclosure relates to an improved design of a rocket motor. More specifically, it relates to a safer and high-performance design of a hybrid rocket motor with an integrated thrust control mechanism.
2. Description of Related Art
Rocket motors may be generally divided into three categories based upon the types of propellant used and the mode of operation: solid, liquid and hybrid rocket motors. In a typical solid rocket motor, solid fuel elements or grains undergo combustion to generate thrust that propels the rocket. A liquid rocket motor generates thrust by combusting liquid fuels. Upon ignition, a typical solid or liquid fuel rocket motor burns the propellants uninterruptedly until all the propellants are exhausted. A hybrid motor, as the name suggests, may be characterized as a cross between a solid and a liquid fuel motor. While most hybrid rocket motors utilize a liquid oxidizer and a solid fuel, some hybrid motors use a combustible liquid fuel and a solid oxidizer.
Although significant progress has been made, many issues remain unsolved with current rocket motor design. The first problem relates to the safe handling and storage of the rocket motors. Most chemicals used in current rocket motors are of a high hazard classification. Moreover, many rocket motors fail to meet the Insensitive Munitions (IM) standard, which refers to insensitivity to shock, fire or penetration by ballistic projectiles. Despite great efforts over the past decades, rocket engineers have not succeeded in making a rocket that meets the IM standard without compromising the performance of the rocket.
The second issue associated with current rocket motor design is the difficulty and high cost required to include a modulation mechanism so that the thrust can be modified during operation of the rocket motor. Because complicated engineering is required to incorporate a thrust-adjusting means, most solid rocket motors do not possess thrust modulation capability. There is therefore a need for a means whereby the rocket thrust can be modulated as needed based on the desired vehicle flight profile.
The third problem arises from combustion products released by most rocket motors which usually contain toxic and corrosive products. These toxic gases may not only damage the launch vehicle, but they are also hazardous to the environment and pose a health risk to the ground workers who are usually exposed to them. Therefore, there is a need for a rocket motor that releases minimal amount of toxic gases during normal operation.
Finally, in order to achieve maximum efficiency, it is important to maintain a consistent oxidizer/fuel ratio during combustion. However, under traditional hybrid rocket motor design, it is difficult to maintain a consistent oxidizer/fuel ratio because the geometry of the solid fuel constantly changes during combustion. There is therefore a need for a design that enables a consistent oxidizer/fuel ratio.